The proposed study is aimed at developing and evaluating a new external fixator, that could be more easily and effectively applied at the early stages of evacuation to specialized facilities, for pediatric critical care and rehabilitation. During the Phase I study, a newly developed external double-needle Iizarov fixator (Pitkin and Gritsanov, 2005) will be tested and further developed. Testing will include "ease-to-apply" and stability of fixation tests, as compared to the external fixator adopted by US Military medicine (Hoffmann II). In the new device, clusters of paired needles replace wires or pins penetrating the bone The fixator is to be applied to the bone periosteum by manual actuators, without drilling the bone and opening of the medullary canal. The new fixator will potentially combine the advantages of the existing half-pin external fixators, which don't require drilling, and the pinless AO external fixator (Alonso and Regazzoni, 1990; Cheung, Wong and Choi, 2001), which doesn't penetrate the medullar canal. The Investigators hypothesize that with the newly developed double-needle fixator, the stability of fixation and simplicity of operating the apparatus will surpass the level of practicality of the external half-pin fixator (Hofmann II) adopted by the US Military Medicine. The hypothesis will be evaluated during the comparative studies on the ease of application and the stability of fixation. If this aim of the Phase I study is achieved, the further study (Phase II) will be conducted to verify the effectiveness of the early application of external fixation. [unreadable] [unreadable] [unreadable] [unreadable]